Mortgage Debt and Notes Payable, Nonrecourse (Details Textual) (USD $) In Thousands, unless otherwise specified			12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2012 Minimum [Member]	Jan. 31, 2012 Maximum [Member]
Debt Instrument [Line Items]
Funds for development and construction projects maturities			2 years	5 years
Mortgage Debt and Notes Payable, Nonrecourse (Textual) [Abstract]
Proceeds from outstanding debt of development projects recorded as restricted cash and escrowed funds	$ 1,646	$ 150,165